#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>

#define MAX_PATH   256
char filename[MAX_PATH + 5];
int main(int argc, char** argv)
{
    //数字字符串转数字
    const  char* kk = "689";
    int zhi = atoi(kk) + 8;

    //数字字符串转double
    double zhi2 = atof(kk) + 2;
    printf("result : %f \n", zhi2);


    //数字转字符串
    int nn = 58;
    char zu[20];
    snprintf(zu,20, "%d", nn);
    printf("%d-----%d-----%s", sizeof(zu),strlen(zu),zu);

    getchar();
    return 0;
}

结果: 

FR：徐海涛(hunkxu)