sprintf函数在字符串处理的妙用

//转化字符串为原来字符+该字符连续出现的次数void TransChar(char* str,int n,char* res){int res_len=0;//结果字符串现有长度int count =1;//当前字符出现的次数for (int i=0;i<n;i++){if (str[i+1]==str[i]){             count++;}else{sprintf(res+res_len,"%c%d",str[i],count);            res_len+=2;count =1;}}}//替换字符串里面的空格为%20,保存在resvoid repalcebank(char* str,int n,char* res){   int res_len=0;//记录存储在res中字符长度     for (int i=0;i<=n;i++)     {         if (str[i]==' ')         {    char sub[]="%20";             sprintf(res+res_len,"%s",sub);//把%20加在res字符串尾端 res_len+=3;         } else {             res[res_len++]=str[i]; }     }    res[res_len]='\0';//添加结束符}int main(){    char a[]="we are happy";char res[20]={'\0'};    repalcebank(a,12,res);return 0;}