c++如何把整数1234转化成字串“1234” c语言问题：将数字字符串（如“1234”）转换为数值型数据怎...
\u5c06\u4e00\u4e2a\u6574\u6570\u5b57\u7b26\u4e32\u8f6c\u6362\u4e3a\u4e00\u4e2a\u6570\uff0c\u5982\u201c\u20141234\u201d\u8f6c\u6362\u4e3a\u20141234\u3002c++\u5b57\u7b26\u4e32\u5982\u4f55\u8f6c\u5316\u4e3a\u6570\u5b57
\u4f60\u53ef\u4ee5\u53eb stringstream \u548c vector \u5e2e\u5fd9\u3002
\u4e0b\u9762\u7684\u4ee3\u7801\u91cc dbl_array \u65e2\u662f\u4f60\u8981\u521b\u5efa\u7684\u5b9e\u6570\u6570\u7ec4\uff08real \u4ee3\u8868\u4f60\u8bfb\u5230\u7684\u5b57\u7b26\u4e32\uff09\u3002
#include
#include
#include
using namespace std;
int main( ) {
string real = "12.32 12 35 25.3 36.366";
stringstream ss( real );
vector vd;
// Collect all real numbers.
double temp;
while( ss >> temp )
vd.push_back( temp );
// Create the array.
double *dbl_array = new double[ vd.size( ) ];
for( int i = 0; i < vd.size( ); ++i )
dbl_array[ i ] = vd[ i ];
}
\u503c\u5f97\u4e00\u63d0\u7684\u662f\uff0cvector \u53ef\u4ee5\u88ab\u5f53\u6210\u6570\u7ec4\u6765\u7528\uff0c\u800c\u4e14\u5b83\u6bd4\u6570\u7ec4\u4f18\u79c0\u5f88\u591a\uff0c\u6240\u4ee5\u4f60\u5927\u53ef\u53bb\u6389\u4e0a\u9762\u7684\u4ee3\u7801\u91cc\u591a\u4f59\u7684\u6700\u540e\u4e00\u6bb5\uff0c\u76f4\u63a5\u7528 vector\u3002
\u6807\u51c6\u5e93Vector\u7c7b\u578b
\u4f7f\u7528\u9700\u8981\u7684\u5934\u6587\u4ef6\uff1a
#include
Vector\uff1aVector \u662f\u4e00\u4e2a\u7c7b\u6a21\u677f\u3002\u4e0d\u662f\u4e00\u79cd\u6570\u636e\u7c7b\u578b\u3002 Vector\u662f\u4e00\u79cd\u6570\u636e\u7c7b\u578b\u3002
\u4e00\u3001 \u5b9a\u4e49\u548c\u521d\u59cb\u5316
Vector v1; //\u9ed8\u8ba4\u6784\u9020\u51fd\u6570v1\u4e3a\u7a7a
Vector v2(v1);//v2\u662fv1\u7684\u4e00\u4e2a\u526f\u672c
Vector v3(n,i);//v3\u5305\u542bn\u4e2a\u503c\u4e3ai\u7684\u5143\u7d20
Vector v4(n); //v4\u542b\u6709n\u4e2a\u503c\u4e3a0\u7684\u5143\u7d20
\u4e8c\u3001 \u503c\u521d\u59cb\u5316
1> \u5982\u679c\u6ca1\u6709\u6307\u5b9a\u5143\u7d20\u521d\u59cb\u5316\u5f0f\uff0c\u6807\u51c6\u5e93\u81ea\u884c\u63d0\u4f9b\u4e00\u4e2a\u521d\u59cb\u5316\u503c\u8fdb\u884c\u503c\u521d\u59cb\u5316\u3002
2> \u5982\u679c\u4fdd\u5b58\u7684\u5f0f\u542b\u6709\u6784\u9020\u51fd\u6570\u7684\u7c7b\u7c7b\u578b\u7684\u5143\u7d20\uff0c\u6807\u51c6\u5e93\u4f7f\u7528\u8be5\u7c7b\u578b\u7684\u6784\u9020\u51fd\u6570\u521d\u59cb\u5316\u3002
3> \u5982\u679c\u4fdd\u5b58\u7684\u5f0f\u6ca1\u6709\u6784\u9020\u51fd\u6570\u7684\u7c7b\u7c7b\u578b\u7684\u5143\u7d20\uff0c\u6807\u51c6\u5e93\u4ea7\u751f\u4e00\u4e2a\u5e26\u521d\u59cb\u503c\u7684\u5bf9\u8c61\uff0c\u4f7f\u7528\u8fd9\u4e2a\u5bf9\u8c61\u8fdb\u884c\u503c\u521d\u59cb\u5316\u3002
\u4e09\u3001Vector\u5bf9\u8c61\u6700\u91cd\u8981\u7684\u51e0\u79cd\u64cd\u4f5c
1. v.push_back(t) \u5728\u6570\u7ec4\u7684\u6700\u540e\u6dfb\u52a0\u4e00\u4e2a\u503c\u4e3at\u7684\u6570\u636e
2. v.size() \u5f53\u524d\u4f7f\u7528\u6570\u636e\u7684\u5927\u5c0f
3. v.empty() \u5224\u65advector\u662f\u5426\u4e3a\u7a7a
4. v[n] \u8fd4\u56dev\u4e2d\u4f4d\u7f6e\u4e3an\u7684\u5143\u7d20
5. v1=v2 \u628av1\u7684\u5143\u7d20\u66ff\u6362\u4e3av2\u5143\u7d20\u7684\u526f\u672c
6. v1==v2 \u5224\u65adv1\u4e0ev2\u662f\u5426\u76f8\u7b49
7. \uff01=\u3001\u3001>= \u4fdd\u6301\u8fd9\u4e9b\u64cd\u4f5c\u7b26\u60ef\u6709\u542b\u4e49
\u56db\u3001\u7b80\u5355\u7a0b\u5e8f\u793a\u4f8b\uff1a\u8bfb\u4e00\u7ec4\u6570\u636e\u5230vector\u5bf9\u8c61\uff0c\u8ba1\u7b97\u5e76\u8f93\u51fa\u6bcf\u5bf9\u76f8\u90bb\u5143\u7d20\u7684\u548c\u3002\u5982\u679c\u8bfb\u5165\u5143\u7d20\u4e2a\u6570\u4e3a\u5947\u6570\uff0c\u5219\u63d0\u793a\u7528\u6237\u6700\u540e\u4e00\u4e2a\u5143\u7d20\u6ca1\u6709\u6c42\u548c\uff0c\u5e76\u8f93\u51fa\u5176\u503c\u3002
#include
#include
using namespace std;
int main()
{
vector ivec;
int ival;
//\u8bfb\u5165\u6570\u636e\u5230vector\u5bf9\u8c61
cout>ival)
ivec.push_back(ival);
//\u8ba1\u7b97\u76f8\u90bb\u5143\u7d20\u7684\u548c\u5e76\u8f93\u51fa
if(ivec.size()==0){
cout<<"No element?!"< return -1;
}
cout<<"Sum of each pair of adjacent elements in the vector:"< for(vector::size_type ix=0;ix cout< if((ix+1)%6==0)
cout< }
if(ivec.size()%2!=0)
cout<
return 0;
}
\u4ee3\u7801\u793a\u4f8b\u5982\u4e0b\uff1a
#include
int fun(char*p)
{
int sum=0;
while(*p!='\0')
{
sum=10*sum+*p-'0';
p++;
}
return sum;
}
void main()
{
char str[20];
int num;
gets(str);
num=fun(str);
printf("%d\n",num);
}
\u62d3\u5c55\u8d44\u6599C\u8bed\u8a00\u662f\u4e00\u95e8\u901a\u7528\u8ba1\u7b97\u673a\u7f16\u7a0b\u8bed\u8a00\uff0c\u5e7f\u6cdb\u5e94\u7528\u4e8e\u5e95\u5c42\u5f00\u53d1\u3002C\u8bed\u8a00\u7684\u8bbe\u8ba1\u76ee\u6807\u662f\u63d0\u4f9b\u4e00\u79cd\u80fd\u4ee5\u7b80\u6613\u7684\u65b9\u5f0f\u7f16\u8bd1\u3001\u5904\u7406\u4f4e\u7ea7\u5b58\u50a8\u5668\u3001\u4ea7\u751f\u5c11\u91cf\u7684\u673a\u5668\u7801\u4ee5\u53ca\u4e0d\u9700\u8981\u4efb\u4f55\u8fd0\u884c\u73af\u5883\u652f\u6301\u4fbf\u80fd\u8fd0\u884c\u7684\u7f16\u7a0b\u8bed\u8a00\u3002
\u5c3d\u7ba1C\u8bed\u8a00\u63d0\u4f9b\u4e86\u8bb8\u591a\u4f4e\u7ea7\u5904\u7406\u7684\u529f\u80fd\uff0c\u4f46\u4ecd\u7136\u4fdd\u6301\u7740\u826f\u597d\u8de8\u5e73\u53f0\u7684\u7279\u6027\uff0c\u4ee5\u4e00\u4e2a\u6807\u51c6\u89c4\u683c\u5199\u51fa\u7684C\u8bed\u8a00\u7a0b\u5e8f\u53ef\u5728\u8bb8\u591a\u7535\u8111\u5e73\u53f0\u4e0a\u8fdb\u884c\u7f16\u8bd1\uff0c\u751a\u81f3\u5305\u542b\u4e00\u4e9b\u5d4c\u5165\u5f0f\u5904\u7406\u5668\uff08\u5355\u7247\u673a\u6216\u79f0MCU\uff09\u4ee5\u53ca\u8d85\u7ea7\u7535\u8111\u7b49\u4f5c\u4e1a\u5e73\u53f0\u3002
\u4e8c\u5341\u4e16\u7eaa\u516b\u5341\u5e74\u4ee3\uff0c\u4e3a\u4e86\u907f\u514d\u5404\u5f00\u53d1\u5382\u5546\u7528\u7684C\u8bed\u8a00\u8bed\u6cd5\u4ea7\u751f\u5dee\u5f02\uff0c\u7531\u7f8e\u56fd\u56fd\u5bb6\u6807\u51c6\u5c40\u4e3aC\u8bed\u8a00\u5236\u5b9a\u4e86\u4e00\u5957\u5b8c\u6574\u7684\u7f8e\u56fd\u56fd\u5bb6\u6807\u51c6\u8bed\u6cd5\uff0c\u79f0\u4e3aANSI C\uff0c\u4f5c\u4e3aC\u8bed\u8a00\u6700\u521d\u7684\u6807\u51c6\u3002 \u76ee\u524d2011\u5e7412\u67088\u65e5\uff0c\u56fd\u9645\u6807\u51c6\u5316\u7ec4\u7ec7\uff08ISO\uff09\u548c\u56fd\u9645\u7535\u5de5\u59d4\u5458\u4f1a\uff08IEC\uff09\u53d1\u5e03\u7684C11\u6807\u51c6\u662fC\u8bed\u8a00\u7684\u7b2c\u4e09\u4e2a\u5b98\u65b9\u6807\u51c6\uff0c\u4e5f\u662fC\u8bed\u8a00\u7684\u6700\u65b0\u6807\u51c6\uff0c\u8be5\u6807\u51c6\u66f4\u597d\u7684\u652f\u6301\u4e86\u6c49\u5b57\u51fd\u6570\u540d\u548c\u6c49\u5b57\u6807\u8bc6\u7b26\uff0c\u4e00\u5b9a\u7a0b\u5ea6\u4e0a\u5b9e\u73b0\u4e86\u6c49\u5b57\u7f16\u7a0b\u3002
C\u8bed\u8a00\u662f\u4e00\u95e8\u9762\u5411\u8fc7\u7a0b\u7684\u8ba1\u7b97\u673a\u7f16\u7a0b\u8bed\u8a00\uff0c\u4e0eC++\uff0cJava\u7b49\u9762\u5411\u5bf9\u8c61\u7684\u7f16\u7a0b\u8bed\u8a00\u6709\u6240\u4e0d\u540c\u3002
\u5176\u7f16\u8bd1\u5668\u4e3b\u8981\u6709Clang\u3001GCC\u3001WIN-TC\u3001SUBLIME\u3001MSVC\u3001Turbo C\u7b49\u3002
函数的原型为 char *itoa(int value, char *string, int radix);
其中 第一个是整型值，就是你要准换的数字；第二个是字符串指针，存储转换后的字符串；第三个是进制标志。
#include <iostream>
#include <stdlib.h>
using namespace std;
void main()
{
int i=1234;
char num[5]={'\0'};
itoa(i,num,10);
cout<<num<<endl;
}
常用的方法，就是itoa函数。
函数的原型为 char *itoa(int value, char *string, int radix);
其中 第一个是整型值，就是你要准换的数字；第二个是字符串指针，存储转换后的字符串；第三个是进制标志。
#include <iostream>
#include <stdlib.h>
using namespace std;
void main()
{
int i=1234;
char num[5]={'\0'};
itoa(i,num,10);
cout<<num<<endl;
}
下面是MSDN中的代码(也有例子):Converts an integer to a string. More secure versions of these functions are available; see _itoa_s, _i64toa_s, _ui64toa_s, _itow_s, _i64tow_s, _ui64tow_s.
char *_itoa(
int value,
char *str,
int radix
);
char *_i64toa(
__int64 value,
char *str,
int radix
);
char * _ui64toa(
unsigned _int64 value,
char *str,
int radix
);
wchar_t * _itow(
int value,
wchar_t *str,
int radix
);
wchar_t * _i64tow(
__int64 value,
wchar_t *str,
int radix
);
wchar_t * _ui64tow(
unsigned __int64 value,
wchar_t *str,
int radix
);
template <size_t size>
char *_itoa(
int value,
char (&str)[size],
int radix
); // C++ only
template <size_t size>
char *_i64toa(
__int64 value,
char (&str)[size],
int radix
); // C++ only
template <size_t size>
char * _ui64toa(
unsigned _int64 value,
char (&str)[size],
int radix
); // C++ only
template <size_t size>
wchar_t * _itow(
int value,
wchar_t (&str)[size],
int radix
); // C++ only
template <size_t size>
wchar_t * _i64tow(
__int64 value,
wchar_t (&str)[size],
int radix
); // C++ only
template <size_t size>
wchar_t * _ui64tow(
unsigned __int64 value,
wchar_t (&str)[size],
int radix
); // C++ only
Parameters
value
Number to be converted.
str
String result.
radix
Base of value; which must be in the range 2–36.
Return Value
Each of these functions returns a pointer to str. There is no error return.
Remarks
The _itoa, _i64toa, and _ui64toa functions convert the digits of the given value argument to a null-terminated character string and stores the result (up to 33 characters for _itoa and 65 for _i64toa and _ui64toa) in str. If radix equals 10 and value is negative, the first character of the stored string is the minus sign ( – ). _itow, _i64tow, and _ui64tow are wide-character versions of _itoa, _i64toa, and _ui64toa, respectively.
Security Note:
To prevent buffer overruns, ensure that the str buffer is large enough to hold the converted digits plus the trailing null-character and a sign character.
In C++, these functions have template overloads that invoke the newer, secure counterparts of these functions. For more information, see Secure Template Overloads.
Tchar.h routine
_UNICODE and _MBCS not defined
_MBCS defined
_UNICODE defined
_itot
_itoa
_itoa
_itow
_i64tot
_i64toa
_i64toa
_i64tow
_ui64tot
_ui64toa
_ui64toa
_ui64tow
Requirements
Routine
Required header
_itoa
<stdlib.h>
_i64toa
<stdlib.h>
_ui64toa
<stdlib.h>
_itow
<stdlib.h>
_i64tow
<stdlib.h>
_ui64tow
<stdlib.h>
For more compatibility information, see Compatibility in the Introduction.
Example
Copy Code
// crt_itoa.c
// compile with: /W3
// This program makes use of the _itoa functions
// in various examples.
#include <string.h>
#include <stdlib.h>
int main( void )
{
char buffer[65];
int r;
for( r=10; r>=2; --r )
{
_itoa( -1, buffer, r ); // C4996
// Note: _itoa is deprecated; consider using _itoa_s instead
printf( "base %d: %s (%d chars)\n", r, buffer, strnlen(buffer, _countof(buffer)) );
}
printf( "\n" );
for( r=10; r>=2; --r )
{
_i64toa( -1L, buffer, r ); // C4996
// Note: _i64toa is deprecated; consider using _i64toa_s
printf( "base %d: %s (%d chars)\n", r, buffer, strnlen(buffer, _countof(buffer)) );
}
printf( "\n" );
for( r=10; r>=2; --r )
{
_ui64toa( 0xffffffffffffffffL, buffer, r ); // C4996
// Note: _ui64toa is deprecated; consider using _ui64toa
printf( "base %d: %s (%d chars)\n", r, buffer, strnlen(buffer, _countof(buffer)) );
}
}
Copy Code
base 10: -1 (2 chars)
base 9: 12068657453 (11 chars)
base 8: 37777777777 (11 chars)
base 7: 211301422353 (12 chars)
base 6: 1550104015503 (13 chars)
base 5: 32244002423140 (14 chars)
base 4: 3333333333333333 (16 chars)
base 3: 102002022201221111210 (21 chars)
base 2: 11111111111111111111111111111111 (32 chars)
base 10: -1 (2 chars)
base 9: 145808576354216723756 (21 chars)
base 8: 1777777777777777777777 (22 chars)
base 7: 45012021522523134134601 (23 chars)
base 6: 3520522010102100444244423 (25 chars)
base 5: 2214220303114400424121122430 (28 chars)
base 4: 33333333333333333333333333333333 (32 chars)
base 3: 11112220022122120101211020120210210211220 (41 chars)
base 2: 1111111111111111111111111111111111111111111111111111111111111111 (64 chars)
base 10: 18446744073709551615 (20 chars)
base 9: 145808576354216723756 (21 chars)
base 8: 1777777777777777777777 (22 chars)
base 7: 45012021522523134134601 (23 chars)
base 6: 3520522010102100444244423 (25 chars)
base 5: 2214220303114400424121122430 (28 chars)
base 4: 33333333333333333333333333333333 (32 chars)
base 3: 11112220022122120101211020120210210211220 (41 chars)
base 2: 1111111111111111111111111111111111111111111111111111111111111111 (64 chars)
.NET Framework Equivalent
System::Convert::ToString
慢慢看吧
方法很多啊。
例如：
CSTRING STMP;
int tmp = 1234;
STMP.FORMAT("%d",tmp );
这样，就把INT型的1234放到CSTRING里了。CSTRING和CHAR就都可以直接转换了。
也可放CHAR里，加油！
思路是这样的，采用一个除10取余的方法来实现：
第一次：1234/10=123,1234%10=4;
第二次：1234/10=12,123%10=3;
第三次：12/10=1,12%10=2;
第四次：1/10=0用于判断循环结束，1%10=1
也就是每次相除的结果作为下一次循环的被除数，每次相除的余数作为字符串……
绛旓細include<stdio.h> include<string.h> main(){ char str[20];int a[20],i;printf("input string:");gets(str);for(i=0;i<20;i++){ a[i]=(int)str[i];printf("%2d ",a[i]);} }
绛旓細char buf[12];int a = 0;memset(buf, 0, sizeof(buf));sprintf(buf, "%x", 0x1234);a = atoi(buf);杩欐牱灏辨妸0x1234 鍙樻垚浜1234
绛旓細include<stdio.h>int main(){int n,s=0; scanf("%d",&n); while(n>0) {printf("%d",n%10); s+=n%10; n/=10; } printf("\n鍚勪綅涔嬪拰=%d\n",s); return 0; }
绛旓細include <stdio.h> unsigned long crol(unsigned long n,unsigned int t){ char s[100],p;p=sprintf(s,"%lu%lu",n,n)/2;t%=p;s[t+p]='\0';sscanf(s+t,"%lu",&n);return n;} int main(){ unsigned long n;scanf("%lu",&n);n=crol(n,1);printf("%lu\n",n);return 0...
绛旓細include "stdio.h"int main (){ int x,y; //x鏄師鏁板瓧锛寉鏄掑簭鍚庣殑鏁板瓧 printf("璇疯緭鍏ュ師鏁板瓧:");scanf("%d",&x) ;if(x>9999) printf("杈撳叆鏁板瓧涓嶈兘瓒呰繃9999");else { for(y=0;x!=0;x=x/10 )y=y*10+x%10;} printf("鍊掑簭鍚庣殑鏁板瓧鏄細%d",y);system("pause");} ...
绛旓細鎮ㄥ彲浠ヤ娇鐢C璇█涓殑鏁存暟杩愮畻鍜屽彇妯℃搷浣滃疄鐜灏嗕竴涓鍥涗綅鏁版媶鍒嗘垚涓や釜涓や綅鏁扮殑鎿嶄綔銆傚叿浣撴潵璇达紝鍙互鎸夌収浠ヤ笅姝ラ杩涜鎷嗗垎锛氬皢鍥涗綅鏁伴櫎浠100锛屽緱鍒板墠涓や綅鏁般傚彲浠ヤ娇鐢ㄦ暣鏁伴櫎娉曡繍绠楃"/"瀹炵幇锛屼緥濡傦細int num = 1234;int num1 = num / 100; // 寰楀埌鐧句綅鍜屽崄浣嶇殑鏁帮紝num1 = 12 灏嗗洓浣嶆暟瀵100鍙栨ā锛...
绛旓細涓嶇敤atoi鍑芥暟锛岄偅灏憋細鎬庝箞璇诲彇瀛楃涓蹭綘鑷繁鍐欙紝淇濆瓨鍦ㄤ竴涓瓧绗︽暟缁刟[]閲屻傞暱搴︿綘鑷繁瀹氾紝鐒跺悗浠巃[0]寮濮嬶紝鎶婃瘡涓间负闈0鐨刟[i]鐨勫煎噺鍘48銆傜劧鍚巔rintf("%d",a[i])灏卞彲浠ヤ簡
绛旓細include<stdio.h> void main(){ int a,b,c,d,e,f,g,h,sum;scanf("%d",&a);if(a>=1000&&a<=9999){ b=a/1000;c=a%10;d=a/1000;e=a/100;f=e%10;g=a/10;h=g%10;sum=c*1000+f*10+h*100+d;printf("杞崲鍚:%d",sum);} else printf("姝ゆ暟涓嶄负4浣嶆暟");} ...
绛旓細{ int i,num,temp=0;printf("Please input a numbers(0<x<9999)");scanf("%d",&num);while(num>=10){ temp=temp*10+num%10;num/=10;} temp=temp*10+num;printf("The number is %d",temp);}
绛旓細include <stdio.h> int main(){ int x=1234;int y=0;y=x%100; //鍏堝彇鍚庝袱浣 y *= 100 ; //鏀惧ぇ100鍊嶅悗锛屽氨鍒颁簡鍓嶉潰 y += x/100 ; //鍐嶅姞涓婂悗涓や綅 printf("杞崲鍚=%d\n" , y );return 0;}
