C语言如何控制保留小数位数？ C语言如何用变量控制小数位数
c\u8bed\u8a00\u5982\u4f55\u63a7\u5236\u5c0f\u6570\u4f4d\u6570\u53ef\u4ee5\u5728\u8f93\u51fa\u65f6\uff0c\u6307\u5b9a\u5c0f\u6570\u70b9\u540e\u7684\u6709\u6548\u4f4d\u6570\uff0c\u5b9e\u73b0\u7cbe\u786e\u5230\u82e5\u5e72\u4f4d\u7684\u6548\u679c\u3002\u8981\u7cbe\u786e\u5230\u5c0f\u6570\u70b9\u540e\u82e5\u5e72\u4f4d\uff0c\u5219\u6570\u636e\u7c7b\u578b\u4e3a\u6d6e\u70b9\u578b\uff0c\u53ef\u80fd\u4e3a\u5355\u7cbe\u5ea6(float)\u6216\u53cc\u7cbe\u5ea6(double)\u3002\u5728C\u8bed\u8a00\u4e2d\uff0c\u4f7f\u7528\u683c\u5f0f\u5316\u8f93\u51fa\u51fd\u6570printf\u6765\u5b9e\u73b0\u8f93\u51fa\u3002\u8f93\u51fa\u683c\u5f0f\u4e3a%.NF1 %\u4e3a\u683c\u5f0f\u5316\u5b57\u7b26\u4e32\u7684\u5f15\u5bfc\u5b57\u7b26\u30022 .N\u8868\u793a\u6307\u5b9a\u663e\u793aN\u4f4d\u5c0f\u6570\u30023 F\u4e3a\u7c7b\u578b\u5b57\u7b26\uff0c\u5bf9\u4e8efloat, F\u503c\u4e3af\uff0c \u5bf9\u4e8edouble\uff0cF\u503c\u4e3alf\u3002\u4e3e\u4f8b:1 \u8981\u8f93\u51fafloat a=1.23234; \u4fdd\u75593\u4f4d\u5c0f\u6570\u7684\u5199\u6cd5\u4e3a\uff1aprintf("%.3f",a);2 \u8f93\u51fadouble b=123.345232; \u4fdd\u75594\u4e3a\u5c0f\u6570\uff0c\u5199\u6cd5\u4e3a\uff1aprintf("%.4lf",b);
\u5148\u628a\u8981\u63a7\u5236\u7684\u6570\u5b57\u5148\u4e58\uff0c\u518d\u53d6\u6574\uff0c\u518d\u9664\u3002
\u6bd4\u5982\uff1a\u628a123.4567\u4fdd\u7559\u4e24\u4f4d
1:\u5148\u628a123.4567\u5269100\u7b49\u4e8e12345.67
2:\u5728\u6570\u5b57\u524d\u9762\u52a0\u4e2a(int)(12345.67)\u53d6\u65743:\u53d6\u6574\u540e\u6570\u5b57\u53d8\u621012345
4:\u6700\u540e\u518d\u628a\u8fd9\u4e2a\u6570\u9664\u4ee5100\u7b49\u4e8e123.45
char format[10] = {0};
float a = 3.14159265;
scanf("%d", &postfix); //读入需要保留的小数位数
sprintf(format, "%%.%df", postfix); //比如输入3，那么format里就是"%.3f"，也就是保留三位小数
printf(format, a);
这个很简单。printf("%.2f\n",x);当然x是float型的。输出就是两位小数。就是在f前+小数点+保留小数的位数。
绛旓細鎺у埗灏忔暟浣嶆暟灏辨槸閫氳繃杈撳嚭鏍煎紡璇存槑绗︽潵瑙勫畾鐨 涓句緥璇存槑濡備笅锛1銆乫loat f1=3.1415926;2銆乫loat f2=1234.1415926;3銆乫loat f3=124.1;4銆乸rintf("%3.4f",f1);//杈撳嚭缁撴灉涓猴細_ _ 3.1416(_琛ㄧず绌烘牸)5銆乸rintf("%3.4f",f2);//杈撳嚭缁撴灉涓猴細1234.1416 6銆乸rintf("%3.4f",f3);//杈撳嚭缁撴灉...
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