UVA - 1586 Molar Mass

题目大意：计算相对分子质量。

解题思路：读入分子式存入数组，遍历数组，当一个数组的一个元素是字母时判断之后的两个元素是 ① 数字 ② 字母 ③ \0 并作出相应的加法处理。

#include<stdio.h>
#include<string.h>
int main() {
int t , i ;
double qua;
char s[85];
scanf("%d",&t);
while( t--) {
scanf("%s",s);
qua = 0.0;
for ( i = 0 ; i < strlen(s) ; i++) {
if( s[i] > 64 ){
if(s[i+1] > 64 || s[i+1] == '\0'){
if( s[i] =='C' ) qua += 12.01;
else if( s[i] == 'H') qua +=  1.008;
else if( s[i] == 'O') qua +=  16.00;
else if( s[i] == 'N') qua +=  14.01;
}

else if( s[i+1] < 65 && s[i+2] < 65  && s[i+2] != '\0') {
if( s[i] =='C' ) qua +=(( int(s[i+1]) - 48 )*10 + (int(s[i+2]) - 48) )*12.01;
else if( s[i] == 'H') qua += ( (int(s[i+1]) - 48)*10 + (int(s[i+2])-48) )*1.008;
else if( s[i] == 'O') qua += ( (int(s[i+1]) - 48)*10 + (int(s[i+2])-48) )*16.00;
else if( s[i] == 'N') qua += ( (int(s[i+1]) - 48)*10 + (int(s[i+2])-48) )*14.01;
i += 2;
}
else if( s[i+1] < 65 && s[i+1] != '\0') {
if( s[i] =='C' ) {qua += (int(s[i+1]) - 48) * 12.01;}
else if( s[i] == 'H') qua += (int(s[i+1]) - 48) * 1.008;
else if( s[i] == 'O') qua += (int(s[i+1]) - 48) * 16.00;
else if( s[i] == 'N') qua += (int(s[i+1]) - 48) * 14.01;
i ++;
}
}

}
printf("%.3f\n",qua);// cout << qua << endl;
}
}

写到这题的时候心里还是感慨颇多呢。高考完一门心思的想学化学，阴差阳错读了软件。才过去一年，好多基础知识都忘了。嗯，软件的一大作用就是辅助传统工业优化，也许以后还有机会和真爱在一起的吧～