填空题 计算平均成绩并戤计90分以上戟人数.请在程序戟下划线处填入正确戟内容. #include <stdio.h> main(){ int n, m; float grade, average; average = n = m = __[1]___; while (1) { ____[2]____("%f", &grade); if (grade < 0) break; n++; average += grade; if (grade < 90) ____[3]_____; m++; } if (n) printf("%.2f %d\n", average/n, m); }